Better color, but flashing line on right

./ffmpeg-2.3.1/ffmpeg -i movie_to_be_animated.mp4 output.gif
ffmpeg version 2.3.1 Copyright (c) 2000-2014 the FFmpeg developers
  built on Aug  6 2014 05:03:40 with gcc 4.6 (Ubuntu/Linaro 4.6.4-1ubuntu1~12.04)
  configuration:
  libavutil      52. 92.100 / 52. 92.100
  libavcodec     55. 69.100 / 55. 69.100
  libavformat    55. 48.100 / 55. 48.100
  libavdevice    55. 13.102 / 55. 13.102
  libavfilter     4. 11.100 /  4. 11.100
  libswscale      2.  6.100 /  2.  6.100
  libswresample   0. 19.100 /  0. 19.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'movie_to_be_animated.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf53.21.1
  Duration: 00:00:12.52, start: 0.000000, bitrate: 963 kb/s
    Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 220x220 [SAR 1:1 DAR 1:1], 960 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc (default)
    Metadata:
      handler_name    : VideoHandler
[swscaler @ 0x1f98360] No accelerated colorspace conversion found from yuv420p to bgr8.
Output #0, gif, to 'output.gif':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf55.48.100
    Stream #0:0(und): Video: gif, bgr8, 220x220 [SAR 1:1 DAR 1:1], q=2-31, 200 kb/s, 25 fps, 100 tbn, 25 tbc (default)
    Metadata:
      handler_name    : VideoHandler
      encoder         : Lavc55.69.100 gif
Stream mapping:
  Stream #0:0 -> #0:0 (h264 (native) -> gif (native))
Press [q] to stop, [?] for help
frame=  313 fps=0.0 q=0.0 Lsize=    1192kB time=00:00:12.52 bitrate= 779.8kbits/s
video:1505kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown